I just looked at the "Original Size" version instead of clicking on the image itself as before. The acute resolution in the wood does look sharp edgy. Due to no AA filter? Perhaps Sigma has taken this too far. I don't see details in reality like this. Detail is fine but do we see this much with our naked eyes? I don't. But then again my style of photography is "sono-mama" (the Japanese aesthetic of things as they are, as-is X). Your mileage/kilometragre may vary...

Reality is much sharper than that photo

Seriously. There are two reasons why the image looks too so sharp when pixel peeping.

If it is sharp, and you look at 100% or even 200%, then you will be aware of pixels. Pixels are square, and at least on most LCD screens are very sharp. This is called output aliasing.

Lack of AA filter might create aliasing when sampling the input image. Input aliasing creates details that are not there. They often look harsh.